1. Field of the Invention
The present invention pertains generally to vises and more specifically, to the jaw of a precision vise such as those used in conjunction with milling machines and the like to accurately locate and retain a workpiece in relation to the cutting tool of such machines.
2. Prior Art
Vises are well-known in the machining tool art and among machinists who use such tools. Precision vises are used in conjunction with machining equipment such as milling machines for the purpose of accurately controlling and retaining a workpiece in a required position relative to the cutting tool of a milling machine and the like in order to make precise changes in the structure of the workpiece. Furthermore, it is well-known that a workpiece must often be oriented at a particular angle with respect to one of its edges within the vise so that a milling cut can be accomplished at a selected angle. For example, it is not uncommon for a machinist to use a milling machine to make a milling cut in a first direction for a given depth within the workpiece and then to have to reorient the piece to change the direction of the next cut to a pre-selected angle relative to the direction of the first cut. It is the reorientation of the workpiece and the accurate, stable positioning thereof that the present invention is designed to facilitate.
Until applicant's present teachings, it has been typical for a machinist operating a milling machine who must reorient the workpiece for the aforementioned changes, to first release the pressure of the vise jaws being applied to the workpiece for retaining it at a particular location and angle with respect to the cutting tool and then to utilize a protractor or other angle measurement device for reorienting the workpiece at the desired new angle, and then to tighten the vise jaws to reapply sufficient pressure on the work piece to retain it in the newly selected angular position. It will be understood by those having skill in the art to which the present invention pertains that such a process suffers from a number of disadvantages. By way of example, additional time is consumed in having a milling machine operator search for and retrieve the appropriate angle measurement instrument and the difficulty of reading that instrument increases the likelihood of inaccuracy in the newly positioned angle for the workpiece. Further inaccuracies commonly occur as a result of the inherent difficulty in properly maintaining the workpiece at the newly selected angle within tolerance limits while retightening the vise jaws. The vise jaws support the workpiece in only a lateral direction providing no underlying platform that can assure stability of the re-selected angle of the workpiece while the vise jaws are tightened. As a result, the prior art procedure commonly employed to reorient a workpiece at a newly selected angle with respect to the cutting tools of a milling machine and the like is inherently costly, requires great care on the part of the machinist and is potentially more likely to reslt in an inaccurate cut because of the difficulty in precisely repositioning the workpiece at the newly selected angle with respect to the cutting tool.